Fixed point theorem for generalized cyclic -contraction maps in complete metric space

 

Ajay Kumar Sharma

Department of Mathematics, Seth Phoolchand College, Navapara Rajim, Dist. Raipur (Chhattisgarh) India

*Corresponding Author Email: sharmakajay17@gmail.com

 

ABSTRACT:

Abstract. The purpose of this paper is to prove some existence and convergence fixed point theorem for generalized cyclic -contraction in complete metric space. Our results generalize and extend some recent results in complete metric space.

 

2000 Mathematics Subject Classification. 47H10, 46J10, 46J15.

 

KEY WORDS:  Metric space, Generalized cyclic contraction, Fixed point theorem

 


1 INTRODUCTION:


In 2003 Kirk-Srinavasan-Veeramani [1] was introduced the notion of cyclic contraction mapping and proved some fixed point theorems for the operators in the class of cyclic contraction. Since then many interesting fixed point theorems for contractive type conditions have been obtained by various authors. The existence and uniqueness of fixed point and common fixed point theorems of operators has been subject of great interest since Banach [2] proved the Banach contraction principle in 1922. A great number of studies concerning fixed points of contractions on different spaces have been represented among those spaces are the metric spaces, quasi-metric space, Cone metric space, Fuzzy metric space, Menger spaces.

 

Let (X,d) be a metric space. A mapping is a contraction if there exists a constant such that

 

holds for any x, y 2 X. If X is complete, then every contraction has a unique fixed point and that point can be obtained as a limit of repeated iteration of the mapping at any point of X. Obviously, every contraction is a continuous function. Generalization of the above principle has been a heavily investigated branch of research. In [3] Boyd and Wong proved that the constant k can be replaced by the use of upper semi-continuous function. In ([4], [5]) generalized Banach contraction conjecture has been established. In [11] Suzuki has proved a generalization of the same principle which characterizes metric completeness. The contraction principle has also been extended to probabilistic metric space [7].

 

Let (X, d) be a metric space. Suppose A and B are nonempty subsets of X. A mapping: is called a cyclic map if and We give the following basic definitions and some important results, which will be used in the our main result.


Definition 1.1 [8].  A function    is called a distance function if the following properties are satisfied :

(a) ,

(b)   is continuous and monotonically non-decreasing.

 

Definition 1.2 [9]. Let (X, d) be metric space, m a positive integer,  closed non-empty subsets of X and . An operator is called a cyclic weak  -contraction if

(i)    is a cyclic representation of Y with respect to T, and

(ii) there exits a continuous, non-decreasing function   with

  for t > 0 and  , such that

,                                             (1.1)

for any , , i = 1, 2, ...,m where .

Notice that the definition above generalizes cyclic  -contraction introduced by Pacurar and Rus [10] by suitable choice of . Karapnar [9] proved the following theorem for the maps given in the previous definition.

 

Theorem 1.3. Let (X, d) be a complete metric space, closed non-empty subsets of X and . Let  be a cyclic generalized weak -contractive mapping, where  is a nondecreasing and continuous function with   for all , and  (0) = 0. Then T has a unique fixed point .

We denote by  the class of all function   such that satisfies the following condition:

.

Obviously, for every     if then by defined we conclude that   and hence . Therefore t = 0. For example, every nondecreasing function   with  for belong to .

 

2. MAIN RESULTS:

In this paper, we introduced the definition of generalized cyclic − contraction and proved unique fixed point for the contractive condition.

 

Definition 2.1. Let (X, d) be a metric space m a positive integer  closed nonempty subsets of X and . An operator  is called a generalized cyclic    contraction if

(i)  is a cyclic representation of Y with respect to T, and

(ii) there exists two function  where    and  is continuous such that

,                                       (2.1)

for all any  for any , , i = 1, 2, ...,m where , and where

 

Theorem 2.2. Let closed nonempty subsets of a complete metric space (X, d). Suppose ,  is continuous and  be a generalized cyclic  − contraction mapping satisfying (2.1). Then T has a unique fixed point .

 

Proof. Suppose an arbitrary and construct the sequence  such that Now using (2.1), for all , we get

                                         (2.2)

where

                      (2.3)

If then from (2.2) and (2.3), we obtain

                                (2.4)

It is clear that

                  (2.5)

and it follows that

,

and this is a contradiction. Therefore , for all . Thus the sequence is decreasing sequence of nonnegative number. So there exits for some  such that

.                                                              (2.6)

Making in (2.4) and using continuity of   and  , we have

which is a contradiction. Hence

.                                                              (2.7)

Next, we show that  is Caucny sequence in (X, d). Then there exists for which we can find subsequences  and  of  with such that for every i,

,                                                              (2.8)

and

,                                                        (2.9)

From (2.8) and (2.9) and the triangular inequality, we have

.

Taking in the above inequality and using (2.8), we get

.                                                                    (2.10)

Again from (2.8) and the triangular inequality, we get that

On letting in the above inequalities and using (2.9) and (2.10), we have

                                      (2.11)

From (2.3), we obtain

                     (2.12)

where

From (2.11) and (2.13), we get

                                                            (2.14)

So that from (2.11), (2.12) and (2.14), we calculate that

.                                                                    (2.15)

Since        , then , which is a contradiction.

This shows that  is a Caucny sequence and hence is convergent in the complete  matric space X. Suppose , as . substituting and in (2.1), we get

where

Since (X, d) is complete and the sequence  is Cauchy, there exists x in X such that . We calculate that for i = 1, 2, ..,m since ,

and is closed. So . For all from (2.1) and , we have

                          (2.16)

where

This inequality shows that . We need to show that .

If then for  , there exists such that for all , .

 Since   is nondecreasing, from (2.16)

                                         (2.17)

 

for all . Letting in above inequality, we obtain

                                                     (2.18)

 

 

and this implies that . This is a contradiction. Hence  , therefore T has a common fixed point.  Uniqueness of the common fixed point follows from 3.1, and this completes the proof.


 


3. REFERENCES:

[1]   Kirk, W.A., Srinavasan, P.S. and Veeramani, P., Fixed points for mapping satisfying cyclical contractive conditions, Fixed point theory, 4 (2003), 79-89.

[2]   Banach, S., Surles operation dans les ensembles ab- stracts etleur application aux equations integrals.Fun.Math,Vol. 3, (1922), 133 - 181.

[3]   D. W. Boyd and J. S. W. Wong, On nonlinear contractions, Proceedings of the American Mathematical Society, vol. 20, no. 2, pp. 458464, 1969.

[4]   A.D. Arvanitakis, A proof of the generalized Banach contraction conjecture, Proceedings of the American Mathematical Society, vol. 131, no. 12, pp. 36473656, 2003.

[5]   J. Merryfield, B. Rothschild, and J. D. Stein Jr., An application of Ramseys theorem to the Banach contraction principle, Proceedings of the American Mathematical Society, vol. 130, no. 4, pp. 927933, 2002.

[6]   T. Suzuki, A generalized Banach contraction principle that characterizes metric completeness, Proceedings of the American Mathematical Society, vol. 136, no. 5, pp. 18611869, 2008.

[7]   O. Hadzic and E. Pap, Fixed Point Theory in Probabilistic Metric Spaces, vol. 536 of Mathematics and Its Applications, Kluwer Academic Publishers, Dordrecht, The Netherlands, 2001.

[8]   M.S. Khan, M. Swaleh, and S. Sessa, Fixed point theorems by altering distances between the points, Bulletin of the Australian Mathematical Society, vol. 30, no. 1, pp. 19, 1984.

[9]   Karapinar, E., Fixed point theory for cyclic weak _-contraction, Appl. Math. Lett. 24(2011), 822-825.

[10]         Pacurar, M. and Rus, I.A., Fixed point theory for cyclic psi-contraction, Nonlinear Anal.(TMA) 72 (2010), 1181-1187.

[11]         Suzuki, T: A generalized Banach contraction principle that characterizes metric completeness. Proc Am Math Soc. 136, 1861186 (2008)


 

 

 

 

Received on 12.03.2013                                    Accepted on 15.04.2013        

Modified on 20.04.2013                          ŠA&V Publications all right reserved

Research J. Science and Tech 5(3): July- Sept., 2013 page 363-367